1. Field of the Invention
The present invention generally relates to a system for cooling components in nautical engines and, in particular, is concerned with a system that cools an externally mounted drive assembly by spraying water collected from the body of water in which the boat is operating on the outer housing of the drive assembly.
2. Description of the Related Art
Most stern drives for propelling boats have three basic components, a motor turning a drive shaft, a drive assembly that is used to transmit the power developed by the motor, and a propeller that receives the engine power from the drive assembly. Typically, for most inboard or inboard/outboard stern drives, the engine is mounted inside of the boat and the housing containing the drive assembly is mounted on the outside of the boat, above the water-line.
The drive assembly will normally include a series of gears that transmit the torque developed by the engine on the drive shaft to a shaft driving the propeller, i.e., the propshaft. The drive assembly is preferably mounted within a watertight housing, and is filled with oil to provide lubrication for the moving gears and shafts. When the motor is operating, frictional forces resulting from interaction between the gears and shafts of the drive assembly generate heat within the housing. As can be appreciated, the frictional heat generated within the housing increases as the boat operates at higher RPMs and power settings.
Unfortunately, excessive heat within the drive assembly will ultimately result in damage to either the gears or shafts, reducing their operating life and necessitating replacement of the drive assembly. In high performance boat engines, replacement of the drive assembly can become prohibitively expensive. Hence, the ability to dissipate the frictional heat developed within the drive assembly housing is desirable to prolong the operational life of the drive assembly.
One particularly useful method of providing cooling for nautical engines and drive components involves taking water from the body of water in which the boat is operating and using this water for cooling purposes. U.S. Pat. No. 4,075,969 provides one example of where water is taken from a lake or ocean and is then used for purposes of cooling the boat's motor.
In addition to its function as a heat transfer medium, other systems have been developed that take water from the lake in which the boat is operating for various other purposes. Specifically, U.S. Pat. No. 4,595,372 discloses a water ejector and injector attachment that includes an opening in the skeg of the boat's engine-mounted trim tab. This attachment however is designed to supply water to, and remove water from, a piping system, preferably connected to the bilge(s) of the boat. The water is collected and removed from the piping system via the ejector/injector attachment using water pressure forces resulting from the movement of the boat through the water.
A need exists in the prior art for a simple apparatus which provides cooling for the drive assembly. Heretofore, while some of the prior art references teach taking water from the lake in which the boat is operating to cool the boat's motor, none of the references of which applicant is aware, teach using this water to cool the drive assembly of the boat's stern drive. Preferably, this inventive apparatus should be readily adaptable to existing boat stern drives and capable of taking water from the lake in which the boat is operating to cool the drive assembly without requiring the use of mechanical pumps, to thereby minimize the cost of the apparatus.